Released this week with stealthily little fanfare, Google's Chromecast is already on back order in the Google Play store, and out of stock on Amazon. The little plastic dongle -- which plugs into your television's HDMI port to beam media like Netflix from a phone, tablet, or PC -- immediately generated immense enthusiasm, with some calling the device, at just $35, a game changer in the nascent field of internet television. Since then, however, a clearer picture has emerged of how exactly Chromecast works.